breathing life into old chips

hi, this is sort of off-topic as it applies to my TV and not a computer, but I bet some of the folks here can offer advice... :) the microcontroller in the set seems to have developed a fault which only appears when the set's warm. Tracking down a replacement seems to be easier said than done as the chip was obviously discontinued a while back (and then I'd have to worry about the on-board ROM anyway). At the moment though there's no heatsink on the chip - if I do stick a heatsink on it in the hope that it keeps it cool enough to operate, is it still likely to fail at a later date anyway? Once a chip's started to exhibit heat-related problems is that basically the end of it even if something's done about the cooling? I figure some of you people will likely know about these things :) (the chip in question is a ST9293J9B1/AEL for the record, but no infomation appears to exist on the web or on ST's site for it; wish I could get pin-outs to check that it is the chip and not surrounding circuitry that's failing) cheers! Jules For a better Internet experience http://www.yahoo.co.uk/btoffer